The concept of vacuum excavation is well known. Many documents disclose soil excavation systems in which a jet of air is directed against a mass of soil by a hand-held nozzle to cause the mass to break up, and in which the loosened soil is collected by entraining it in an air flow carried by a pipe or conduit, and depositing the entrained soil at a site away from the excavation site.
Additionally, the theory underlying the concept of vacuum excavation is well-known. Indeed, application of supersonic or high pressured jets of air causes local fracturing of the soil and rapid release of expanding high pressure air trapped within the soil at the local fracture sites. The fracturing and gas-release properties of the soil are not shared by man-made structures buried within the soil, such as natural gas lines, water pipes, sewer lines, electric cables, fiber optic and the like, and thus these structures are unaffected by the supersonic or high pressured air jets. It is to be noted that many accidents/explosions have occurred when workers were trying to mechanically dig near natural gas lines.
Loosening of the soil by local fracturing and rapid expansion of gases trapped in the soil rather than by direct impact means that the air delivery device generates relatively low reaction forces and are often manipulated by a single person. Vacuum excavation therefore increases productivity relative to hand-excavation methods, such as, without limitation, shovels, without sacrificing precision, significantly reducing visible alteration of local landscaping or paving. In addition, the use of a high vacuum for material collection causes an effective evacuation of solid material from difficult to reach areas such as beneath or behind pipes, where shovels cannot fit or are difficult to maneuver. Large truck mounted aero-excavators are widely used.
Despite these advantages, however, the conventional vacuum excavation systems have a number of disadvantages that have prevented their widespread use. Using such conventional vacuum excavation systems may lead to inaccurate work. They can also be used only in limited workspaces and may not be allowed in hard to reach locations.
Firstly, conventional vacuum excavation systems usually include dependent vacuum systems and soil breaking systems, which renders the device inefficient as the vacuum systems and the soil breaking systems cannot be operated efficiently at the same time. Also, the conventional vacuum systems now on the market are most of the time heavy, over dimensioned, difficult to managed by one single worker and difficult to displace in areas where the dimensions are a restriction (i.e., in a backyard, in a garage, and the like). Venturi based systems don't allow soil breaking and vacuum at the same time or require two air compressors. On the other hand, large systems (i.e., Vacmasters) include air compressor and vacuum at the same time.
Secondly, conventional vacuum excavation systems usually come on a trailer or are mounted on motorized 4-wheel drive chassis for allowing the worker/driver to maneuver it while walking behind it (i.e., some are propelled like a snow blower). Mainly, they come as dump truck sized custom build on trailers. This configuration of the systems renders the work harder for the workers when on the excavation sites.
Thirdly, usually, the soil breaking systems integrate a venturi and a compressor, which renders the system very heavy.
There is therefore a need for improved excavation devices for fracturing and removing soil material and for improved methods of operating excavation devices for fracturing and removing soil material.